Crimping terminal for coaxial cable



June 23, 1970 I MANCINI 3,517,375

CRIMPING TERMINAL FOR COAXIAL CABLE Filed Jan. 29, 1968 5A/////////////AUk A INVENTOR LLOYD MANCINI United States Patent O 3,517,375 CRIMPINGTERMINAL FOR COAXIAL CABLE Lloyd Mancini, New Cumberland, Pa., assignorto Berg Electronics, Inc., New Cumberland, Pa., a corporation ofPennsylvania Filed Jan. 29, 1968, Ser. No. 701,356 Int. Cl. H01r 17/18U.S. Cl. 339-177 17 Claims ABSTRCT OF THE DISCLOSURE A crimp typeterminal and method for forming an electrical connection with thecylindrical sleeve or shield of a coaxial cable. When crimped to a baredbraided sleeve the terminal collapses a medial portion `thereof to forman annular collar. The terminal is crimped to the collar to establish anelectrical connection.

BACKGROUND OF THE INVENTION Conventionally electrical connections areestablished with coaxial cable braid by means of a solder connection orby inserting a iirst crimping sleeve under an end of the braid,positioning a second crimping sleeve over the braid, and then crimpingthe sleeves together to sandwich the braid therebetween.

A solder connection with the braid requires removal of a portion of thebraid `from the cable to form a pigtail for physical connection with awire or terminal, following which the joint is soldered. This type ofconnection is time-consuming to make and often results in an imperfectelectrical connection between the terminal and the braid. Likewise theconcentric sleeve type connection is expensive in terms of labor costsince the sleeves are positioned manually on the cable and then crimpedtogether. Examples of conventional electrical connections for Ibraid areshown in Manzi, Marsman & Brenner, Grounding Sheathed Cable, pp.128-130, Electrical Manufacturing, December 1952.

SUMMARY OF THE INVENTION The invention relates to a crimp type terminaland method for establishing an electrical connection with a wrapped orbraided sleeve. The terminal is applied to a bared portion of the sleeveso that it grips the sleeve at spaced locations and is then collapsedaxially to collapse the medial portion of the sleeve and form anoutwardly projecting double thickness collar of sleeve material. Aportion of the collapsed terminal is crimped to each side of the collarto establish the electrical connection. The terminal may be providedwith a contact portion for establishing anelectrical connection with acircuit element.

The crimping terminal according to the invention is easily and quicklyapplied to the sleeve and forms a reliable electrical connectiontherewith without the necessity of manual assembly or a solderingoperation. When the terminal is used to establish an electricalconnection with the sleeve at an end of the coaxial cable, the free endof the sleeve is moved axially away from the end of the cable duringattachment of the terminal so as to prevent accidental short circuitingbetween the axial conductor and the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of aterminal according to the invention;

FIG. 2 is a perspective view of the terminal of FIG. 1 attached to abared end of a braided conductor of a clzyoaxial cable prior tocollapsing of the terminal and raid;

Patented June 23, 1970 FIG. 3 is similar to FIG. 2 with the terminal andbraid collapsed;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a perspective view of a modified terminal for attachment tothe braid conductor of a coaxial cable; and

FIG. 7 is a side view showing the terminal of FIG. 6 secured to thebraid.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Elongate U-shaped crimpingterminal 10 is formed from sheet metal stock and includes a pair ofspaced U-shaped crimping barrels 12 and 14 joined together by aplurality of outwardly bent leg portions 16 which are spaced around theperiphery of the terminal. Axially opposed contact ilanges 18 extendoutwardly of the adjacent edges of barrels 12 and 14 and are inclinedtoward each other to improve contact with the braid. Braid grippingteeth 20 are provided on the interior surface of each barrel 12 and 14adjacent the leg portions 16. As indicated most clearly in FIG. 4, theteeth 20 have a braid gripping face 21 for preventing movement of thebraid relative to the barrel during collapsing of the terminal. Teeth 20may be formed from the metal stock of the barrels 12 and 14 by apunching operation which also forms recesses 22 on the outer surface ofthe barrels. A suitable contact means 23, such as a pin disconnect, maybe provided in order to establish an electrical connection between theterminal 10 and a circuit element.

The terminal is useful in establishing an electrical connection with abared portion of the shield or braided sleeve conductor conventionallyused in a coaxially cable 24 of the type shown in FIG. 2, having aninner or axial conductor 26. A pair of dielectric spacers 28 are woundaround the conductor 26 in the form of helixes to locate the conductorcentrally within the bore of cylindrical insulator 30. Flexible sleeveor ground conductor 32 encases the insulator 30 so as to preventexternal elds from affecting the si-gnal carried by cable 24. An outerinsulating sheath 34 may be provided. Spacers 28 are used to locate thecentral conductor 26 accurately relative to the insulator 30 and sleeve32 in order to maintain a desired impedance for the cable.

The sleeve 32 surrounds the dielectric material 30 rather loosely topermit ready bending of the cable. It may be woven from groups of exibleconductor strands to form a loose mesh braid as shown in the drawings,or may be formed from flexible conductor strands which are wound aroundthe dielectric insulator 30 to form a sheath. In the latter case it isdesirable that the cable be provided with an outer insulator 34 toconline the wound conductor strands and prevent unraveling of thesleeve. The terminal described herein is effective in establishing anelectrical connection with either a woven or Wound sleeve. While twoforms of coaxial cable shielding have been disclosed, the invention isnot limited by the type of sleeve to which the terminal is secured. Theterminal may be used to establish an electrical connection withcollapsible conductive cylindrical sleeves other than the two formsmentioned. While the invention is particularly useful in establishing anelectrical connection with the outer conductor of a coaxial cable, it isnot intended to be limited to that use. It can be used wherever it isdesirable to form an electrical connection with a flexible sleeveconductor.

Because sleeve 32 is used as one of the two conductors of the coaxialcable 24, it is necessary to form an electrical connection with thesleeve at the end of the cable.

3 To establish a connection -between a terminal and the end of theconductive sleeve of cable 24, a portion of the insulation 34 is removedfrom the end of the cable 24 a distance slightly -greater than thelength of the terminal 10. The terminal is then placed around theexposed braid of sleeve 32 and barrels 12 and 14 are crimped closely toa generally circular cross section so that the teeth 20 engage the braidand prevent movement of the braid relative to the barrels. The terminalis then secured to the cable as illustrated in FIG. 2.

After the terminal is crimped to braid 32, the bar- Iels 12 and 14 aremoved together to collapse the interconnecting leg portions 16 and tocollapse the medial portion 36 of the braid 32 located between barrels12 and 14. As the barrels are moved together the sheath collapses toform a double thickness annular collar 38 `which is confined betweenopposite straight leg portions 40 of the legs 16. Before collapsing ofthe legs 16, portions 40 in each leg define an obtuse angle. When theterminal is fully collapsed as in FIG. 4, the portions 40 are generallyparallel to each other and sandwich the collar 38 therebetween toestablish an electrical connection.

Upon movement of the barrels 12 and 14 toward each other, the medialportion 36 of the cylindrical sleeve 32 is readily collapsed to form thedouble thickness collar 38. During collapsing of the terminal and sleevethe teeth 20 in each barrel 12 and 14 engage the sleeve and prevent itfrom slipping relative to the barrels so as to assure that the medialportion 36 is collapsed to form collar 38.

During collapsing of the terminal and sleeve the medial portion 36 isrst bowed outwardly of the cable so that as the inclined flanges 18 arebrought together they engage the sleeve 32. With further collapsing ofthe terminal and sleeve, flanges 18 tightly sandwich the collar 38 andare bent back from their original position. The bending of the flanges18 during collapsing of the terminal assures that the collar 38 isyconfined therebetween under spring tension and improves the electricalconnection between the flanges and the collar. In the collapsed terminal10, barrels 12 and 14 are held closely together by legs 16 so that theflanges 18 establish an electrical connection with the collar 38.

An electrical connection between the terminal 10 and the sleeve 32 isestablished at each of the leg portions 16 and at each adjacent pair offlanges 18. As shown in FIG. 5, the flanges and legs of the terminal arespaced around the circumference of the cable 24 so that the terminalforms an electrical connection with the sleeve around essentially itsentire circumferential extent. This is an important feature since it isdesirable that the entire sleeve fonm part of the circuit in order toattain desired impedance and shielding. If a single connection isestablished with one circumferential portion of the sleeve, there is noassurance that the connection will place the entire sleeve at the samepotential since the sleeve comprises a plurality of conductors which arenot directly connected to one another. Terminal 10 insures that areliable electrical connection is established with essentially all ofthe conductors in sleeve 32.

Because the electrical contacts between the sleeve 32 and terminal 10are formed in a radial plane and the contact forces establishing theseconnections are essentially axial, the radial geometry of the cable 24is not substantially distorted by. the attachment of the terminal to thecable. In this way the terminal 10 affects the impedance of the cable 24to a minimum extent. When the terminal is crimped to the cable theopposing edges 42 of the barrels 12 and 14 are brought into contact toassure that teeth 20 rmly seat in the sleeve 32. When the crimping forceis removed, the barrels relax slightly and the edges 42 separate to aslight degree. Crimping of the terminal on the cable results in a slightcompression of dielectric insulator 30 as indicated in FIG. 4. Suchdistortion does not result in appreciable changes in impedance. Inconventional crimp type connectors for establishing contact with thesleeve of a coaxial cable, :the electrical connection is formed as theresult of a radial force likely to greatly distort the geometry of thecable and change the impedance of the cable.

As the terminal is collapsed the free end 44 of sleeve 32 is movedaxially away from the free end of the cable 24 as a result of theshortening of the sleeve when the collar 38 is formed. By moving thesleeve 32 away from the end of the cable, the likelihood of shortcircuits occurring between the sleeve and axial conductor 26 is reduced.This feature of the invention is important since it eliminates thenecessity of checking each terminal when attached to a braid to becertain that there is no accidental short circuiting between the sleeveand the central conductor as a result of unraveling of the sleeve.

FIG. -6 illustrates a terminal 50 comprising an arcuate U-shapedcrimping 4'barrel 52 with a portion 54 extending therefrom. The barrel52 may be tted over a part of an annular collar 56 formed in aconductive sleeve 58 of coaxial cable 60. The barrel 52 is then crimpedto bring side or leg portions 62 thereof into intimate contact with thecollar to establish an electrical connection therewith. A circuitelement may be attached to a contact on portion 54.

Terminal 50 is mounted directly on the annular collar 56 formed in thesleeve of cable 60 and does not touch the body of the cable. Thusterminals 50 may be used in situations where it is highly desirable thatthe impedance of the cable not be affected at all by terminals securedto the conductive sheath.

While I have illustrated and described preferred embodiments of myinvention, it is understood that these are capable of modification and Itherefore do not 4wish to be limited to the precise details set forth.

What I claim as my invention is:

1. A terminal for establishing an electrical connection with a flexibleconductive sleeve, comprising an axially collapsible terminal bodyadapted to ibe mounted on said sleeve in surrounding relation theretoand having portions at each end therefor engageable with said sleeve toprevent relative movement therebetween, collapsible leg means joiningsaid terminal portions to permit movement of said terminal portions andthe engaged portions of the sleeve toward each other to bunch a medialportion of the sleeve into an annular outwardly projecting collar, andcontact means on said terminal portions adapted to engage and establishan electrical connection with said collar.

2. A terminal according to claim 1 wherein said terminal portions areadapted to be crimped to said sleeve and are provided wtih means thereonengageable with said sleeve to prevent relative movement between saidterminal portions and said sleeve when said terminal body is collapsed.

3. A terminal according to claim 1 including a plurality of said contactmeans on each of said terminal portions with each contact means axiallyaligned with one of the contact means on the other terminal portion.

4. A terminal according to claim 3 wherein said contact means areadapted to establish said electrical connection with substantially theentire circumferential extent of said collar.

5. A terminal according to claim 3 wherein said contact means compriseflanges projecting outwardly of said terminal portions at spacedintervals along the opposing edges of said terminal portions.

6. A terminal according to claim 3 wherein said leg means comprise apair of integral angularly related legs extending from said terminalportions and adapted to be bent outwardly into generally parallelrelation as said terminal body is collapsed to sandwich said collartherebetween to provide said electrical connection.

7. A terminal according to claim 6 wherein a plurality of said leg meansare spaced along and extend from the opposing edges of said terminalportions.

8. A terminal according to claim 7 including opposed pairs of angesprojecting outwardly from said terminal portions, each pair of flangesbeing disposed between adjacent pairs of said leg means and adapted tosandwich said collar therebetween to establish an electrical connectiontherewith.

9. An electrical contact system comprising a cable having a conductivesleeve surrounding a cylindrical insulator, an annular collar formedfrom a collapsed medial portion of said sleeve with parts of said sleeveextending axially along the cable to either side of said collar, saidcollar comprising a pair of flattened sleeve portions, each of whichextends circumferentially around said insulator and projects radiallyoutwardly therefrom, and a circumferential bight portion joining saidattened portions outwardly of said insulator, the inner surfaces of saidattened portions abutting each other at an interface, and a terminalcrimped to the opposite sides of said collar to sandwich said collarbetween opposing terminal portions and establish an electricalconnection between the terminal and the sleeve.

10. An electrical contact system as in claim 9 wherein said contactmeans comprises a plurality of U-shaped legs joining said terminalportions and engaging opposite sides of said collar, said terminalportions extending around said sleeve and being crimped thereto,gripping means on the inner surface of said terminal portions to preventaxial movement of said portions relative to said sleeve, and flangemeans extending outwardly of each of said terminal portions adjacentsaid collar and located between adjacent legs on each terminal portion,said flange means being biased into engagement with said collar toestablish an electrical connection therewith.

11. An electrical contact system as in claim 9 wherein said terminal isdisposed in surrounding relation to said sleeve and includes portions oneach side of said collar physically engaging said sleeve to preventrelative movement therebetween, and contact means extending outwardlyfrom said portions in electrical contact with said collar.

12. An electrical contact system as in claim 11 wherein said contactmeans comprises a U-shaped leg joining said terminal portions andengaging opposite sides of said collar.

13. An electrical contact system comprising a exible conductive sleeve,a double thickness medial portion of said sleeve extendingcircumferentially around said sleeve and projecting radially outwardlytherefrom to form a at radial collar, and a terminal disposed insurrounding relation to said sleeve, said terminal including portions oneach side of said collar crimped to said sleeve, said portions includinggripping means on the inner surfaces thereof to engage said sleeve andprevent axial movement relative thereto, and contact means extendingoutwardly from said portions adjacent said collar for electrical contactwith said collar.

14. A method of forming an electrical connection between a terminal anda collapsible cylindrical conductive sleeve comprising the steps ofaxially collapsing a medial portion of the sleeve to form a doublethickness annular collar extending radially outwardly from the sleeveand circumferentially around the sleeve with the sides of the collarflat against each other and cylindrical portions of the sleeve extendingaxially to either side of the collar, positioning portions of a terminalto each side of the collar, crimping the terminal to the collar tosandwich the collar between said portions of the terminal and establishelectrical connections between the terminal and both sides of thecollar.

15. A method for forming an electrical connection with a collapsibleconductive sleeve comprising the steps of crimping spaced portions of aterminal to the sleeve and moving such portions together to collapse themedial portion of the sleeve between said portions and form a doublethickness annular collar, and securing a portion of the terminal inelectrical connection with both sides of the collar.

16. A method of forming an electrical connection between an electricalterminal and a ilexible conductive sleeve which comprises placing theterminal on the sleeve in surrounding relation thereto, engaging axiallyspaced portions of the terminal with corresponding portions of thesleeve, moving said portions of the terminal and sleeve toward eachother to bunch a medial portion of the sleeve into an annular outwardlyextending collar while at the same time sandwiching said collar betweenopposed electrical contact means on said terminal portions.

17. A method according to claim 16 including the step of crimping saidaxially spaced portions of the terminal around said sleeve.

References Cited UNITED STATES PATENTS 2,678,963 5/1954 Everhart 174-483,109,052 10/1963 Dumire et al. 174-882 3,141,924 7/1964 Forney 174-75FOREIGN PATENTS 980,381 1/ 1965 Great Britain.

RICHARD E. MOORE, Primary Examiner lI. H. MCGLYNN, Assistant ExaminerU.S. Cl. X.R. 339-276

